As a result of a new law, Texas employers have been amending their workplace violence policies so employees can store legally owned guns in their vehicles while they are at work.

The law, which went into effect Sept. 1, is intended to provide extra security for commuters who drive through dangerous neighborhoods on their way to and from the workplace.

More than a dozen states already have such laws, and adding Texas to that group was a major coup for the gun rights lobby. Two previous bills had failed in the Legislature before SB 321—known as the Employee Parking Lot Bill—passed in May and was signed into law by Gov. Rick Perry.

But guns-in-the-workplace laws have caused confusion and court battles in other states. And employment law experts say the Texas law could create major challenges for management.

"Employers will need to be more vigilant in monitoring the workplace," predicts Joseph Gagnon, who is of counsel at the law firm Fisher & Phillips in Houston. Jokes, threats and other communications between employees should be examined closely for signs of potential workplace violence, he says. "HR and managers may have to become amateur psychologists."

The Texas law is part of a backlash against firearm bans that many U.S. employers imposed after a series of widely publicized school and workplace shootings in the 1990s. In 2008, a federal judge upheld a Florida law that allows employees holding a concealed-weapons permit to keep a gun locked in their parked vehicle and, in 2009, a federal appeals court said a similar Oklahoma law does not conflict with the Occupational Safety & Health Administration's standard on workplace violence.

"OSHA has not indicated in any way that employers should prohibit firearms from company parking lots," the court ruled.

The Texas law states that an employer cannot prohibit an employee who has a concealed handgun license or "otherwise lawfully possesses a firearm" from storing the weapon "in a locked, privately owned motor vehicle in a parking lot, parking garage or other parking area the employer provides for employees."

Employer groups including the Texas Association of Business vigorously opposed the bill, arguing that it conflicts with the obligation of employers to provide a safe workplace. But in the Legislature, commuter safety trumped those concerns. The bill recognizes that "a worker's individual and constitutional right to self-defense does not end when they drive onto their employer's property," an official with the National Rifle Association said in a written statement.

Employers were somewhat assuaged by a provision in the law that, except in cases of "gross negligence," an employer is immune from liability for injury or death involving a firearm that an employee brought to work. "The legislation does have very strong liability language in there," says Cathy DeWitt, vice president of governmental affairs for the Texas Association of Business. Certain employers, including school districts, chemical manufacturers and oil refiners are exempt from the law.

Gagnon says some employers have taken a "wait-and-see" attitude toward the law.

"There's disagreement about whether the law provides employees with a private cause of action against employers" who do not comply with the law, he explains. There is no specific provision for a private lawsuit, he says, and employers could delay compliance until they know "how the state is going to enforce this."

A major concern for employers, experts say, is that an angry employee will no longer have to go home to retrieve a firearm. If the weapon is immediately available in the employee's car, the worker will not have a "cooling-off" period. That makes employer vigilance all the more important, Gagnon argues. "Substance abuse [by employees] will probably be an area of focus," he says. And, Gagnon says, "employees should be required to present documentation that shows they are legitimately entitled to carry a firearm. If you don't do that, [a firearm-related injury] may raise to the level of gross negligence."

Karen Denney, a partner at the law firm Haynes and Boone in Fort Worth, Texas, says employers who have a general prohibition on guns in the workplace should add an exception to their policies that "says employees may have lawfully possessed firearms in locked parked vehicles." She says she doesn't believe additional vigilance or employee monitoring is necessary. "Employers already do criminal background checks," she notes. "The incentive [for workplace security] is already there."

But in DeWitt's view, there will be "more stringent" pre-employment screening of employees as a result of the law. And she says she believes employers will be quicker to terminate employees who exhibit a potential for violent behavior. "They might be fired immediately."

"Employers are concerned about unintended consequences" of the law, Gagnon says. "It's going to be interesting to see how this plays out."